1. Field of the Invention
This invention relates to computerized control systems and, more particularly, to numerical control systems for machines.
2. Description of the Prior Art
Machine automation has been widely used in the prior art such as with numerical controls for machine tools. These prior art controls are special purpose (non-computerized) devices with solid state electronics, relays, and other such devices; but without stored program digital computers. The special purpose devices do not fully utilize time sharing, therefore requiring special circuitry for each function implemented, resulting in a large number of expensive circuits each performing a special purpose function. For the numerical control of machine tools, these special purpose controls have been standardized for use with many different machines. The requirements of each type of machine are usually different, requiring a different interface to convert the standard control system signals into the special signals required by the machine. This interface is usually implemented with relays and mounted on the machine as an integral part of the machine, commonly known in the art as "the machine magnetics" or simply "the magnetics". The magnetics have been accepted in the numerical control field as a necessary part of the system, where the need for magnetics is not disputed in the prior art.
For numerical control systems that control machine tools, digital commands are input with a punched tape to describe the part to be cut on the machine such as a milling machine. These commands are accessed by the numerical control system and are executed to drive the machine to automatically cut the part.
Prior art numerical control systems have been designed around special purpose digital devices where operations such as logic, control, and computations are performed with special purpose logic. Because of the high cost and limited capability of these special purpose numerical control systems, the data is preprocessed with a remote, large scale computer using a parts program complier such as APT. The remote computer preprocesses the information and generates a punched tape in a control oriented language (EIA) containing the initial conditions and commands required by the special purpose numerical control equipment. These parts program tapes describe the part to be generated and are used as the command inputs to the numerical control system to cut the part.
Well known documents on numerical control are listed below and are incorporated herein by reference.